Allied Force's Second Enemy: the Weather

The Allied Expeditionary Force battled two stubborn foes. One of
them, the Germans, was reasonably predictable. The other, the
weather, defied close analysis and for that reason gave the Allied high
command the kind of trouble it had hoped to avoid.

Supplies and reinforcements were moving across the Channel and up the
beaches in great volume. Even the Germans admitted that. But the
Allied high command made no bones of a sobering fact: unloading had
been thrown behind schedule.